Screw-cutting machine



(No Model.)

J. DELKER.

sGRBW CUTTING MACHINE. No. 253,987. v Patented Feb. 2131882.

Fig.2.

UNITED STATES PATENT OFFICE.

JOHN DELKER, OF ST. LOUIS, MISSOURI.

SCREW-CUTTING MACHINE.

SPECIFICATION forming part of Letters. Patent No. 253,987, dated February 21, 1882.

Application filed June 16, 1881.

' To all whom it may concern My invention relates to improved means for securing the die-holders to their supportinglevers.

My improvement consists in oscillating levers and die-holders having ton gue-and-socket connection, and having a locking device securing them together, so as to be readily removed and replaced, as hereinafter described.

In the drawings, Figurel is afront view of the die-holders in position for forming the thread, the jaws being closed. Fig. 2 is a side view of the die-holders, showing parts in section. Fig. 3 is a section at w 00, showing the jaws open to allow the retreat of the screw-threaded bar. Fig. 4 is a side view of the machine-head in which the die-holder levers have bearing. Fig. 5 is a front view of the die-holders, showing the dies open. Fig. 6 is a top view of the machine-head.

A is the fixed head of the machine, giving bearing to the die-holder levers B, which oscillate on fulcrum-pins G.

D is a plug or cone, which is thrust in be tween the feet E to keep them asunder, and thus keep the die-heads in contact with each other, as shown in Figs. 1, 2, and 4 in position to work the threads on the dies.

When a thread has been worked a sufficient distance back from the point of the bolt said point of the bolt impinges against the end of the adjustable screw-rod D, sorewedthrough the cone D. When the cone is pushed back by the advancing bolt the feet E are free to approach each other, and such movement is induced by springs F, which bear against side pins, G, extending from the levers through slots in the housing or machine-head A. As the feet E approach each other the die-holders I separate, releasing the bolt from the dies. Then the bolt can be run back from between the dies.

I will now describe my improvements in the above. I form on the end of the lever B a (No model.)

dovetail tenon, I), fitting tightly a channel or socket, 'i, of the holder I, so that when the holder is upon the lever there will be no shake between the two. Through the jaws t z" and the tenon b, I bore a conical hole, in which I insert a conical pin or key, K, to lock the holder on the lever. The pin K has a small recess in the larger end, which receives a teat, l, at the end of a spring, L, said spring holding the pin inits hole.

I do not claim broadly the use of more than two dies in a threading apparatus, for -I am aware that thisis old 5 but I believe this feature to be novel in this combination or connection, in which it has special value, because the dies in the removable holder require no adjustment, as every size of bolt has its special die-holders, whereas where the holders are not adapted to be quickly removed and replaced the dies must be adjusted to different sizes of bolts, and consequently they are made as few in number as practicable to save time and simplify the adjustment.

Practically frequent changes are demanded in the use of most threading-machines, and much skilled labor is expended in the adjustment of the dies, and morebr less imperfect work turned out. With my improvement no skilled labor is required to change the machine for threading a bolt of any size, and but a very little time, and no imperfect work is turned out.

The means for the locking and the adjustment of the die are not claimed as new.

Having thus described my invention, the following is what I claim as new therein and desire to secure by Letters Patent:

1. The combination, with the oscillating levers B B, of the removable die-holders I I, the said levers and holders having tongue-andsocket connection and a suitable locking device inserted through the tongues and sockets, as set forth.

2. The combination of tapering key or pin K with the lever B and die-holder I, the said pin adapted to be'withdrawn and forming the device for securing the holder to the lever, as set forth.

Witnesses:

SAML. KNIGHT, GEo. H. KNIGHT.

JOHN DELKER. 

